Aspirin – all you need to know

Aspirin, discovered as salicylic acid in willow bark, has been used for centuries to relieve pain and fever.

It’s a non-steroidal anti-inflammatory drug (NSAID) and, like other NSAIDs such as ibuprofen, it can help to make us feel better when we have colds, flu, headache or toothache, or suppress joint swelling and damage in rheumatoid and other forms of arthritis.

It’s also now routinely used for many other conditions, and it’s even been suggested that we should all take a daily aspirin.

But although its role as ‘wonder drug’ is still expanding, it has side effects too (see below), so we shouldn’t take it regularly, except on medical advice after a personalised assessment of our potential risks and benefits.

Cardiovascular prevention

Aspirin makes blood platelet cells less ‘sticky’ so they’re less likely to form blood clots inside arteries that trigger cardiovascular ‘events’ such as heart attacks and strokes.

It’s prescribed on its own, usually 75mg daily, or with other anti-platelet drugs such as clopidogrel and dipyridamole, for specific cardiovascular diseases (CVDs), according to national guidelines.

These include angina (heart pain on exertion), or after a heart attack or coronary artery bypass or stenting (tube inserted to widen the artery).

It’s also prescribed after a transient ischaemic attack (mini-stroke) to protect against a full stroke, for some forms of stroke (diagnosed using a CT scan) and for peripheral vascular disease (circulation problems in the legs).

It’s sometimes used to treat abnormal heart rhythms when full anti-coagulation (blood- thinning drugs) isn’t suitable, and to prevent recurrent miscarriage in women who have anti-phospholipid syndrome.

But it’s not recommended for people who aren’t known to have CVD (‘primary’ prevention), as the risks usually outweigh the benefits.

Aspirin and cancer

Research has shown that people who take aspirin regularly may be less likely to develop cancer, and are more likely to be diagnosed at an early stage if they do develop the disease, which may also be less likely to spread.

But it’s not yet clear which types are most susceptible to its effects, what the recommended dose might be, whether it does any good in people under the age of 50 (so far, evidence suggests probably not), and whether for most of us, the potential harms could outweigh the benefits.

But it’s a very exciting development and, of course, large-scale, long-term research trials have been set up to see whether aspirin should become a routine treatment/preventer in some forms of cancer.

Side effects and risks

Aspirin can cause stomach inflammation, nausea, indigestion and/or dangerous internal bleeding, so people who really need to take it may also be prescribed acid-suppressing medicines to help protect them.

As it also affects blood clotting, people who take it may bruise or bleed more readily (for example, nosebleeds) and have a slightly raised risk of brain haemorrhage.

There’s also a small risk of allergic reactions such as an itchy rash, wheezing or the (rare) life-threatening anaphylaxis.